pH, Oxygen and OUR Monitoring in Shake Flasks, Cultivation Tubes and T-flasks

SFR Shake Flask Reader

The SFR Shake Flask Reader monitors pH, oxygen and OUR in up to 9 Erlenmeyer flasks, cultivation tubes, or T-flasks simultaneously. It fits in nearly all standard shakers. Measurement data is transferred wirelessly via Bluetooth to your PC / notebook. The corresponding ready-to-use vessels contain pre-calibrated sensor spots. The system monitors non-invasively through the transparent bottom of the container. Different types and sizes of flasks and tubes are available. Plastic, disposable flasks contain pre-calibrated oxygen and pH sensors, while re-usable glass flasks are equipped with autoclavable oxygen sensors.

  • Fast monitoring of up to 63 shake flasks in parallel
  • For microbial and cell culture
  • Pre-calibrated cultivation vessels are ready-to-use
  • Compatible with standard shakers
  • Glass & plastic flasks in different sizes available
  • Non-invasive measurement
  • Used in seed train & bioprocess development


Process Monitoring in Suspension-Adapted CHO Cell Cultures

The online measurement of dissolved oxygen concentration and pH in shaken bioreactors paves the way for proper scale down activities from bench-top stirred-tanks to smaller scales. Adjustment of shaking speed as a function of pO2 is now possible avoiding possible oxygen limitations at high cell densities. Even a simple pH readjustment by tuning the pCO2 in the incubator is feasible to optimize the output from simple experiments with shaken bioreactors.
Dr. Robert Puskeiler, Roche Diagnostics, Penzberg, Germany

Yeast & E. coli: Ensure Enough Oxygen Supply

S. cerevisiae grows on different sugars as carbon source. While growth on glucose and fructose is mainly fermentative, growth on galactose is mainly respirative. This leads to low oxygen concentration in the shake flasks. The accurately measured oxygen indicates the need to increase rotation frequency to avoid oxygen limitation.

High oxygen demand is typical for E. coli in its exponential phase. In the cultivation shown on the left, rotation speed had to be changed twice in order to avoid oxygen limitation. In addition, changes in the metabolism can be detected by measuring DO.

Schneider et al., University of Saarland, Saarbrücken, GermanyBioprocess Biosyst Eng., 33(5), 541 - 547, 2009



* provided Sensor Flasks are used without further handling in physiological solutions
** at 100 rpm & in cell culture media

Measurement range0 – 100 % O25.5 – 8.0 pH
Response time (t90) at 25 °C< 60 sec.< 60 sec.

± 0.01 % O2 at 0.21 % O2
± 0.1 % O2 at 20.9 % O2

± 0.01 pH at pH = 7**

± 0.4 % O2 at 20.9 % O2
± 0.05 % O2 at 0.2 % O2

± 0.1 pH at pH = 7 with one-point adjustment

± 0.2 pH at pH = 7 with pre-calibration
Drift< 0.01 % O2 per day (sampling interval of 1 min.)< 0.01 pH per day (sampling interval of 1 min.)
Temperature rangefrom + 5 °C to + 50 °C
CompatibilityAqueous solutions, ethanol (max. 10 % v/v), methanol (max. 10 % v/v), pH 2 - 4
Cross-sensitivityTypically no cross-sensitivity in culture mediaReduced to ionic strength (salinity); a high concentration of small fluorescent molecules in the visible range can interfere
Sensor flasks are delivered irradiated

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Calibration Data

SFS v3/v4
iTubes pH

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